Opencv升级到4.2遇到的相关问题整理

遇到一个记一个0.0
1、升级Opencv到4.2后遇到undefined reference to cv::error(int, cv::String const&, char const*, char const*, int)' (.text._ZN2cv3MatC2ENS_5Size_IiEEiPvm[_ZN2cv3MatC5ENS_5Size_IiEEiPvm]+0x1cf): undefined reference tocv::String::deallocate()’
解决方案：
增加头文件

#include 

2、error: ‘CV_RETR_TREE’ was not declared in this scope
增加

#include 

3、CV_LOAD_IMAGE_COLOR在Opencv4.x中不能用了

// bgrImage = cv::imdecode(vecInputData, CV_LOAD_IMAGE_COLOR);        // opencv3.3
bgrImage = cv::imdecode(vecInputData, cv::IMREAD_COLOR);              // opencv4x